Process validation is next control required by the ISO 13485 Standard, and an effective process validation contributes significantly to ensuring the quality of the medical device. Validation means testing that expected results and objectives have been achieved. The intention is clear: the organization is required to validate realization processes where the results and outputs cannot be controlled at the end of the process or that have a finished product that cannot be monitored, measured, and verified. For example, after sterilization and packaging (sterile barrier) activities, it is impossible to open each medical device and test the level of sterility. This is why we take the control one step backward and ensure the level of sterility through process parameters. In order to ensure that the process is acting according to the specification and providing the expected results, we must validate it.
Process validation
Process validation is the systematic planned collection and evaluation of data of processes during the realization, which establishes evidence that a process is capable of consistently delivering its expected results. Process validation is conducted as a set of activities taking place over the life-cycle of the product and process. The objective is to gain a defined degree of assurance in the performance of a process. This assurance will be obtained from objective information and data demonstrating that processes are capable of consistently producing products within specifications.
Validation circle
In order to initiate and implement effective validations of your processes, the matter must be considered by several parties related to the realization processes of the medical device. Each one will share its opinions and aspects on the matter, and together you will plan an effective validation system that will capture your processes. In the book I suggest a structure for the validation circle and specify who is to participate.
Evaluating and identifying processes for validation
The validation processes must refer to processes where deficiencies become apparent only after the product is in use or the service has been delivered. The main concept of the ISO 13485 Standard is determining that each realization step is controlled to ensure that each process’s results and eventually the finished product will meet all its quality attributes and specifications. The validation provides the assurance that the medical device and its components, characteristics, intended use, performance, and safety cannot be adequately assured merely by in-process and finished-product inspection or testing. The first step is to examine the impact of a process on the quality of the medical device. When the influence of a process on the medical device is considerable or critical and application of control will affect the quality of the medical device, it needs to be controlled. Before we plan the validation of a process, we must whether we need to validate or verify it. In other words, identifying processes for validation is the determination of whether a process can be verified or validated. What is the difference between a process that needs to be verified and one that needs to be validated? The rule of thumb is to ask whether a process can be verified with monitoring and measurement activities or needs to be validated. I prepared here a scheme that describes the process for such evaluation. A very effective diagram for evaluating whether a process needs to be validated or verified is included below. The outputs of this evaluation shall provide a list of processes that must be validated. Sample a process and introduce it to the following flow chart (Figure 7.5).
Process parameters for validation
The parameters of the process affect the performance of the process; thus, the parameters are related directly to the quality, functionality, performance, safety, and intended use requirements. After defining the processes that need to be validated, it is required that you define for each one the parameters that will be controlled. The parameters should be evaluated in terms of their roles in the process and impact on the process results. In order to implement effective validations, you must understand what the key parameters affecting the quality of the product or the performance of a process are, for example, temperature, pressure, compounds of raw material, concentrations, tension, time, machine cycle, and setup conditions. Identifying key parameters will help you indicate what is to be measured.
To begin with, review and analyze the effect of each process on the specifications and characteristics of the product. For example, the sealing process of the package will affect the quality of the product, its performance, and its intended use. Values and levels for these characteristics should have already been determined (e.g., outputs of design phase). In order to reach these specifications of characteristics, the sealing process must maintain certain conditions; for example, during the sealing process, the temperature and the pressure of the clamps are critical in order to reach the required level of strength. When determining the parameters for control, it is important to correlate the inputs with the outputs. For example, in a plastic molding, the injection formation of the part is affected by the holding time of the part on the production tool before opening and releasing the part (a fraction of a second can be critical). The input (holding time) is directly related to the output (form of the part). These parameters will indicate the stability of a process; thus, these parameters will need to be controlled. After identifying these parameters, it is necessary to relate them to the tools and the elements (in the process) that are influenced by those parameters, namely, machines, software, production tools, human resources, and infrastructures. These elements will supply us with the data and results regarding the process parameters.
Acceptance criteria for review and approval of processes
After identifying the parameters for validation, you need to determine and document, for each process, the target values and their acceptance criteria. Target values are the optimal values for the process parameter. These values will demonstrate the stability and capability of a process and ensure that requirements are met and accepted. Maintaining process parameters within the criteria ensures that it will deliver expected product characteristics and specifications. The criteria are used for evaluation of the results compared to the requirements. The limits of the criteria (target values, upper and lower control limits) are based on product or process specifications. The objectives of the criteria are to demonstrate the effectiveness of processes and support decisions for judging, evaluating, and determining by facts, values, and data the compliance of the processes. I suggest in the book an effective method for planning and implementing acceptance criteria.
Other topics that are discussed and reviewed with examples in the book:
- Worst-case conditions
- Selecting a method for analyzing the data
- Determining sample size
- Establishing documented procedures for process validation
- Records of validation
- Developing a validation plan
- Approval of changes to the processes
- Installation Qualification
- Operational Qualification
- Performance Qualification
- Validation of software applications; Context and scope, documented procedures, Validation of software prior to initial use or after changes,
- Proportionate validation to risk analysis
- Revalidation and periodic revalidation
- Particular requirements for validation of processes for sterilization and sterile barrier systems
This webpage contains only a fragment of the chapter 7 Product realization from the book:ISO 13485:2016: A Complete Guide to Quality Management in the Medical Device Industry, Second Edition published by:
Comments are closed.